TOPIC INFO (UGC NET)
TOPIC INFO – UGC NET (Psychology)
SUB-TOPIC INFO – Biological Basis of Behaviour (UNIT 4)
CONTENT TYPE – Detailed Notes
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1. The Central Nervous System
1.1. CNS Functions
1.2. The Brain
1.3. Spinal Cord
1.4. How the CNS Communicates with the Body
1.5. Disorders & Damage
1.6. How the Central Nervous System is Protected
2. Peripheral Nervous System (PNS)
2.1. What does the PNS do?
2.2. Parts and Divisions of the Peripheral Nervous System
2.3. Central Nervous System vs Peripheral Nervous System
2.4. Nerves in the Peripheral Nervous System
2.5. Importance of PNS
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The Central and Peripheral Nervous System
UGC NET PSYCHOLOGY
Biological Basis of Behavior (UNIT 4)
The Central Nervous System
- The central nervous system (CNS) is the body’s command center. It includes the brain and spinal cord, which work together to control movement, sensation, thought, and emotion.
- By processing information from the senses, the CNS coordinates everything from voluntary actions like walking to automatic functions like breathing and heartbeat.
- Without the CNS, we wouldn’t be able to think, feel, or respond to the world. It connects our mental and physical experiences – making it essential not just for survival, but for how we experience life.
CNS Functions
- The Central Nervous System (CNS), composed of the brain and spinal cord, functions as the body’s primary control centre.
- It is responsible for receiving and interpreting sensory information, making decisions, and directing the body’s muscular and physiological responses.
- The CNS operates through a continuous cycle of receiving input, processing that data, and initiating output.
1. Core Physiological Functions:
The CNS is responsible for both high-level cognitive processes and the maintenance of internal stability (homeostasis).
- Reflex Coordination: The spinal cord facilitates rapid, involuntary responses to stimuli—such as the withdrawal reflex—bypassing the brain for immediate action.
- Sensory Processing: The system receives and interprets data gathered by the peripheral nervous system regarding the environment and the body’s internal state.
- Integration (The Processing Phase): The brain integrates current sensations with existing emotions and memories to form a complete picture of the environment.
- Cognition: Information reaching the brain is processed by the cerebral cortex to create consciousness, reasoning, and language. Uses integrated data to solve problems or use language.
- Motor Command: The brain initiates signals that travel through the spinal cord to trigger voluntary movements (e.g., speech) and regulate involuntary muscle actions.
- Homeostatic Regulation: The hypothalamus maintains internal equilibrium (body temperature, hunger, thirst) by working with the autonomic nervous system.
2. Component Roles:
The CNS is divided into two primary anatomical components with specialized roles:
The Brain:
- Acts as the primary site for higher-order functions including intelligence, personality, and emotion.
- Manages the interpretation of complex sensory data and the production of speech.
The Spinal Cord:
- Functions as the vital communication relay, carrying messages bidirectionally between the brain and the rest of the body.
- Serves as the independent center for coordinating spinal reflexes.
3. Protection and Metabolic Support:
Because the CNS is composed of delicate neural tissue, it requires extensive physical and physiological protection:
- Physical Armor: The brain is encased within the skull, and the spinal cord is protected by the vertebral column (vertebrae).
- Meninges: Three protective membranes (dura mater, arachnoid mater, and pia mater) surround the CNS to provide a barrier against injury.
- Nutrient Dependency: The CNS has a high metabolic rate and is heavily reliant on a constant supply of nutrients and oxygen to function.